HMS Riou off Greenock, Scotland, on 22 May 1944.
History
United States
Name	unnamed (DE-92)
Ordered	10 January 1942[1]
Builder	Bethlehem-Hingham Shipyard, Hingham, Massachusetts
Laid down	4 August 1943[2]
Launched	23 October 1943[2]
Completed	14 December 1943[2]
Commissioned	never
Fate	Transferred to United Kingdom 14 December 1943[2]
Acquired	Returned by United Kingdom 25 February 1946[2]
Stricken	28 March 1946[2]
Fate	Sold for scrapping 21 April 1947[2]
United Kingdom
Name	HMS Riou (K557)
Namesake	Captain Edward Riou (1762–1801), British naval officer who was killed in action as commanding officer of HMS Amazon during the Battle of Copenhagen in 1801[3]
Acquired	14 December 1943[2]
Commissioned	14 December 1943[1]
Fate	Returned to United States 25 February 1946[2]
General characteristics
Displacement	1,400 long tons (1,422 t)
Length	306 ft (93 m)
Beam	36.75 ft (11.2 m)
Draught	9 ft (2.7 m)
Propulsion	Two Foster-Wheeler Express "D"-type water-tube boilers GE 13,500 shp (10,070 kW) steam turbines and generators (9,200 kW) Electric motors for 12,000 shp (8,900 kW) Two shafts
Speed	24 knots (44 km/h)
Range	5,500 nautical miles (10,200 km) at 15 knots (28 km/h)
Complement	186
Sensors and processing systems	SA & SL type radars Type 144 series Asdic MF Direction Finding antenna HF Direction Finding Type FH 4 antenna
Armament	3 × 3 in (76 mm) /50 Mk.22 guns 1 × twin Bofors 40 mm mount Mk.I 7–16 × 20 mm Oerlikon guns Mark 10 Hedgehog antisubmarine mortar Depth charges QF 2-pounder naval gun
Notes	Pennant number K557

HMS Riou (K557) was a British Captain-class frigate of the Royal Navy in commission during World War II. Originally constructed as a United States Navy Buckley class destroyer escort, she served in the Royal Navy from 1943 to 1945.

The ship was laid down as the unnamed U.S. Navy destroyer escort DE-92 by Bethlehem-Hingham Shipyard, Inc., in Hingham, Massachusetts, on 4 August 1943 and launched on 23 October 1943.^[2] She was transferred to the United Kingdom upon completion on 14 December 1943.^[2]

Commissioned into service in the Royal Navy as the frigate HMS Riou (K557) on 14 December 1943 simultaneously with her transfer, the ship served on patrol and escort duty for the remainder of World War II.^[1][2]

The Royal Navy returned Riou to the U.S. Navy on 25 February 1946.^[2]

The U.S. Navy struck Riou from its Naval Vessel Register on 28 March 1946. She was sold on 21 April 1947 for scrapping.^[2]

• Navsource Online: Destroyer Escort Photo Archive Riou (DE-92) HMS Riou (K-557)
• uboat.net HMS Riou (K 557)
• Destroyer Escort Sailors Association DEs for UK^[usurped]
• Captain Class Frigate Association HMS Riou K557 (DE 92)

• Photo gallery of HMS Riou (K557)